Twitter has had global impact in ways that never could have been imagined since the first tweets in March 2006. Now, with hundreds of millions of active Twitter users and tweets numbering over 500 million per day, we easily become tempted to follow so many accounts that it can become too noisy to be useful.

Looking for some guidance on a maximal number of accounts to follow on Twitter, I came across Dunbar’s number. This is a theory by British anthropologist Dr. Robin Dunbar that there is a “cognitive limit to the number of people we can maintain social relationships,” in which brain size “limits the number of relationships that an individual can monitor simultaneously” (PDF). He felt that this number was around 150 relationships in humans, although proposed numbers range anywhere between 100-230. The term Monkeysphere was coined in reference to an experiment confirming this correlation between brain size and social groups in monkeys.

Dunbar looked at whether his proposed cognitive limit also applies to Facebook, and wrote:

Facebook itself did a survey of its accounts about a year ago and found that the average number of friends was between 120 and 130.

The odd reality is that we are actually not capable of managing more friendships than you typically see on Facebook now—or more than people have traditionally maintained.

And concluded that:

If you have more than 150, it is because you are including people who have no meaningful relationship with you.

I don’t think there is a “correct” way to use Twitter, but given it has become my primary source of incoming information, I try to be thoughtful about both who I follow and how many I follow. Looking at an October 2012 study, the average Twitter user follows about 102 accounts, which is well within Dunbar’s observations. I certainly start to feel a bit of cognitive strain when the number I’m following is too high (which is most of the time).

My approach to Twitter is to generally focus on following thought leaders for topics I’m interested in, and have a low threshold to unfollow an account unless I’m finding they consistently add value to my network.

When you first start to filter your network and unfollow accounts on Twitter, you’ll be a bit nervous that you’ll miss something. Trust me, you won’t. If something is important, your well selected network is going to amplify that message and you’ll see it.